Phase Change Test Study Guide

Freedom of movement

The way molecules in a substance move around relative to each other.

Kinetic energy

The energy that an object has because it is moving.

Molecular Attraction

A pull between two molecules that is always the same for a substance.

Molecule

A group of atoms joined together in a particular way.

Phase

A noticeably different form or state of the same substance.

Scale

The relative size of things.

Temperature

A measure of how hot or cold something is.

What happens to the molecules of a substance when it changes phase?

The freedom of movement changes.

How can we tell how fast the molecules move if we can’t see them?

The temperature can help us because when they are hot, they move a lot.

Why does an energy transfer not always result in a phase change?

When there's too much or too little molecular attraction.

What happens if energy is added from a glass of ice water?

The phase of the ice water would change into gas.

What happens if energy is removed from a glass of ice water?

The phase would change into a solid.

Which particles have the more kinetic energy?

Particles of steam.

Which order of phases has the particles moving from FASTEST to SLOWEST?

Gas-Liquid-Solid.

What happened when you transfer the same amount of energy out of two liquids at room temperature, but only one changes phase?

The substance with the weaker attraction will change to a gas.

Which model shows a phase change occurring?

Model A shows phase change because it shows it being liquid rather than turning into gas.

What does this diagram show about molecular attraction?

Different liquids have different molecular attractions.

When you transfer energy into a substance, the molecules’ kinetic energy increases __________.

Kinetic energy increases.

When you transfer energy into a substance, the temperature _______ increases _____________.

Temperature increases.

When the kinetic energy of molecules decreases, the molecules are moving _____________.

Slower.

When a substance changes from one physical form to another, we say the substance has had a(n) ___________ phase change _____________.

Phase change.